Which of the following best defines pressure? (Chemistry)

Which of the following best defines pressure?
A) It is the total amount of heat per unit area held by a substance.
B) It is the force applied to a unit area of surface.
C) It is the average kinetic energy of molecules.
D) It is equal to volume divided by the product of moles and temperature.

*The Answer is B but can someone explain why each one is wrong and why B is right. Only D seems to make sense to me.